Commit Graph

24273 Commits

Author SHA1 Message Date
Steven Wu d0804aa6dc [MachO] Emit Weak ReadOnlyWithRel to ConstDataSection
Summary:
Darwin dynamic linker can handle weak symbols in ConstDataSection.
ReadonReadOnlyWithRel symbols should be emitted in ConstDataSection
instead of normal DataSection.

rdar://problem/39298457

Reviewers: dexonsmith, kledzik

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D45472

llvm-svn: 329752
2018-04-10 20:16:35 +00:00
Krzysztof Parzyszek 71a4c0ca07 [CodeGen] Fix printing bundles in MIR output
Delay printing the newline until after the opening bracket was
printed, e.g.
  BUNDLE implicit-def $r1, implicit-def $r21, implicit $r1 {
    renamable $r1 = S2_asr_i_r renamable $r1, 1
    renamable $r21 = A2_tfrsi 0
  }
instead of
  BUNDLE implicit-def $r1, implicit-def $r21, implicit $r1
 {    renamable $r1 = S2_asr_i_r renamable $r1, 1
    renamable $r21 = A2_tfrsi 0
  }

llvm-svn: 329719
2018-04-10 16:46:13 +00:00
Pavel Labath b7243ed2f4 [CodeGen/Dwarf] Rename the "sizetype" synthetic type and add it to the accelerator table
Summary:
This type is created on-demand and used as the base type for array
ranges. Since it is "special", its construction did not go through the
createTypeDIE function and so it was never inserted into the accelerator
table, although it clearly belongs there.

I add an explicit addAccelType call to insert it into the table.

During review, we also decided to rename the type to something more
unique to avoid confusion in case the user has own "sizetype" type. The
new name for the type size __ARRAY_SIZE_TYPE__.

Reviewers: JDevlieghere, aprantl, dblaikie

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D45445

llvm-svn: 329705
2018-04-10 14:23:41 +00:00
Chandler Carruth 19618fc639 [x86] Introduce a pass to begin more systematically fixing PR36028 and similar issues.
The key idea is to lower COPY nodes populating EFLAGS by scanning the
uses of EFLAGS and introducing dedicated code to preserve the necessary
state in a GPR. In the vast majority of cases, these uses are cmovCC and
jCC instructions. For such cases, we can very easily save and restore
the necessary information by simply inserting a setCC into a GPR where
the original flags are live, and then testing that GPR directly to feed
the cmov or conditional branch.

However, things are a bit more tricky if arithmetic is using the flags.
This patch handles the vast majority of cases that seem to come up in
practice: adc, adcx, adox, rcl, and rcr; all without taking advantage of
partially preserved EFLAGS as LLVM doesn't currently model that at all.

There are a large number of operations that techinaclly observe EFLAGS
currently but shouldn't in this case -- they typically are using DF.
Currently, they will not be handled by this approach. However, I have
never seen this issue come up in practice. It is already pretty rare to
have these patterns come up in practical code with LLVM. I had to resort
to writing MIR tests to cover most of the logic in this pass already.
I suspect even with its current amount of coverage of arithmetic users
of EFLAGS it will be a significant improvement over the current use of
pushf/popf. It will also produce substantially faster code in most of
the common patterns.

This patch also removes all of the old lowering for EFLAGS copies, and
the hack that forced us to use a frame pointer when EFLAGS copies were
found anywhere in a function so that the dynamic stack adjustment wasn't
a problem. None of this is needed as we now lower all of these copies
directly in MI and without require stack adjustments.

Lots of thanks to Reid who came up with several aspects of this
approach, and Craig who helped me work out a couple of things tripping
me up while working on this.

Differential Revision: https://reviews.llvm.org/D45146

llvm-svn: 329657
2018-04-10 01:41:17 +00:00
Daniel Sanders 5281b02e84 [globalisel][legalizerinfo] Add support for the Lower action in getActionDefinitionsBuilder() and use it in AArch64.
Lower is slightly odd. It often doesn't change the type but the lowerings
do use the new type to decide what code to create. Treat it like a mutation
but provide convenience functions that re-use the existing type.

Re-uses the existing tests:
test/CodeGen/AArch64/GlobalISel/legalize-rem.mir
test/CodeGen/AArch64/GlobalISel//legalize-mul.mir
test/CodeGen/AArch64/GlobalISel//legalize-cmpxchg-with-success.mir

llvm-svn: 329623
2018-04-09 21:10:09 +00:00
Matt Arsenault 97b6b1b926 Fix printing of stack id in MachineFrameInfo
uint8_t is printed as a char, so it needs to be
casted to do the right thing.

llvm-svn: 329622
2018-04-09 21:04:30 +00:00
Alexandre Ganea d9e96741c4 [Debuginfo][COFF] Minimal serialization support for precompiled types records
This change adds support for the LF_PRECOMP and LF_ENDPRECOMP records required
to read/write Microsoft precompiled types .objs.
See https://en.wikipedia.org/wiki/Precompiled_header#Microsoft_Visual_C_and_C++

This also adds handling for the .debug$P section, which is actually a .debug$T
section in disguise, found only in precompiled .objs.

Differential Revision: https://reviews.llvm.org/D45283

llvm-svn: 329613
2018-04-09 20:17:56 +00:00
Daniel Sanders c01efe690f Fix type mismatch between MachineMemOperand constructor and accessors. NFC
This allows MachineMemOperand::getSize()'s result to be fed directly into 
MachineMemOperand::MachineMemOperand() without a narrowing type conversion
warning.

llvm-svn: 329602
2018-04-09 18:42:19 +00:00
Aditya Nandakumar b1c467dbe7 [GISel] Refactor MachineIRBuilder to allow transformations while
building.

https://reviews.llvm.org/D45067

This change attempts to do two things:
1) It separates out the state that is stored in the
MachineIRBuilder(InsertionPt, MF, MRI, InsertFunction etc) into a
separate object called MachineIRBuilderState.
2) Add the ability to constant fold operations while building instructions
(optionally). MachineIRBuilder is now refactored into a MachineIRBuilderBase
which contains lots of non foldable build methods and their implementation.
Instructions which can be constant folded/transformed are now in a class
called FoldableInstructionBuilder which uses CRTP to use the implementation
of the derived class for buildBinaryOps. Additionally buildInstr in the derived
class can be used to implement other kinds of transformations.

Also because of separation of state, given a MachineIRBuilder in an API,
if one wishes to use another MachineIRBuilder, a new one can be
constructed from the state locally. For eg,

void doFoo(MachineIRBuilder &B) {
  MyCustomBuilder CustomB(B.getState());
  // Use CustomB for building.
}

reviewed by : aemerson

llvm-svn: 329596
2018-04-09 17:30:56 +00:00
Simon Pilgrim 23c2182c2b Support generic expansion of ordered vector reduction (PR36732)
Without the fast math flags, the llvm.experimental.vector.reduce.fadd/fmul intrinsic expansions must be expanded in order.

This patch scalarizes the reduction, applying the accumulator at the start of the sequence: ((((Acc + Scl[0]) + Scl[1]) + Scl[2]) + ) ... + Scl[NumElts-1]

Differential Revision: https://reviews.llvm.org/D45366

llvm-svn: 329585
2018-04-09 15:44:20 +00:00
Zaara Syeda 935474fef5 [MachineLICM] Re-enable hoisting of constant stores
This patch fixes an issue exposed on the SystemZ build bots when committing
https://reviews.llvm.org/rL327856. The hoisting was temporarily disabled with
an option. This patch now re-enables hoisting and checks that we only hoist a
store instruction when all its operands are either constant caller preserved
registers or immediates.

Differential Revision: https://reviews.llvm.org/D45286

llvm-svn: 329577
2018-04-09 14:50:02 +00:00
Pavel Labath eadfac8748 [CodeGen/AccelTable] Don't emit zero-CU name indexes
Summary:
If an input DICompileUnit is completely empty (e.g., the result of
running "clang -g" on an empty file), we don't bother emitting an empty
DWARF CU. When we do that, we must make sure we don't also emit a DWARF v5
name index, as DWARF specifies that each index must reference at least
one compilation unit.

Reviewers: JDevlieghere, aprantl, dblaikie

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D45435

llvm-svn: 329575
2018-04-09 14:38:53 +00:00
Pavel Labath 889bf9fe00 [CodeGen/AccelTable]: Don't emit accelerator entries for functions with no names
Summary:
We were emitting accelerator entries for functions with no name, which
is contrary to the DWARF v5 spec: "All other (i.e., *not*
DW_TAG_namespace) debugging information entries without a DW_AT_name
attribute are excluded." Besides that, a name table entry with an empty
string as a key is fairly useless.

We can sometimes end up with functions which have a DW_AT_linkage_name but no
DW_AT_name. One such example is the global-constructor-initialization functions,
which C++ compilers synthesize for each compilation unit with global
constructors.
A very strict reading of the DWARF v5 spec would suggest that we should not even
emit the accelerator entry for the linkage name in this case, but I don't think
we should go that far.

I found this when running the dwarf verifier over llvm codebase compiled
with DWARF v5 accelerator tables.

Reviewers: JDevlieghere, aprantl, dblaikie

Subscribers: vleschuk, clayborg, echristo, probinson, llvm-commits

Differential Revision: https://reviews.llvm.org/D45367

llvm-svn: 329552
2018-04-09 08:41:57 +00:00
Sam Parker 1f4f4d9a08 [DAGCombine] Improve ReduceLoad for SRL
Recommitting r329283, third time lucky...

If the SRL node is only used by an AND, we may be able to set the
ExtVT to the width of the mask, making the AND redundant. To support
this, another check has been added in isLegalNarrowLoad which queries
whether the load is valid.

Differential Revision: https://reviews.llvm.org/D41350

llvm-svn: 329551
2018-04-09 08:16:11 +00:00
Michael Zolotukhin 8d052a0dd2 Remove MachineLoopInfo dependency from AsmPrinter.
Summary:
Currently MachineLoopInfo is used in only two places:
1) for computing IsBasicBlockInsideInnermostLoop field of MCCodePaddingContext, and it is never used.
2) in emitBasicBlockLoopComments, which is called only if `isVerbose()` is true.
Despite that, we currently have a dependency on MachineLoopInfo, which makes
pass manager to compute it and MachineDominator Tree. This patch removes the
use (1) and makes the use (2) lazy, thus avoiding some redundant
recomputations.

Reviewers: opaparo, gadi.haber, rafael, craig.topper, zvi

Subscribers: rengolin, javed.absar, hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D44812

llvm-svn: 329542
2018-04-09 00:54:47 +00:00
Sanjay Patel 0d7df36c66 [TargetSchedule] shrink interface for init(); NFCI
The TargetSchedModel is always initialized using the TargetSubtargetInfo's 
MCSchedModel and TargetInstrInfo, so we don't need to extract those and 
pass 3 parameters to init().

Differential Revision: https://reviews.llvm.org/D44789

llvm-svn: 329540
2018-04-08 19:56:04 +00:00
Zvi Rackover 7a53f169f1 DAGCombiner: Combine SDIV with non-splat vector pow2 divisor
Summary:
Extend existing SDIV combine for pow2 constant divider to handle
non-splat vectors of pow2 constants.

Reviewers: RKSimon, craig.topper, spatel, hfinkel, efriedma

Reviewed By: RKSimon

Subscribers: magabari, llvm-commits

Differential Revision: https://reviews.llvm.org/D42479

llvm-svn: 329525
2018-04-08 11:35:20 +00:00
Guozhi Wei 0eb86c8efc [DAGCombiner] Fold (zext (and/or/xor (shl/shr (load x), cst), cst))
In our real world application, we found the following optimization is missed in DAGCombiner

(zext (and/or/xor (shl/shr (load x), cst), cst)) -> (and/or/xor (shl/shr (zextload x), (zext cst)), (zext cst))

If the user of original zext is an add, it may enable further lea optimization on x86.

This patch add a new function CombineZExtLogicopShiftLoad to do this optimization.

Differential Revision: https://reviews.llvm.org/D44402

llvm-svn: 329516
2018-04-07 23:36:10 +00:00
Craig Topper 5b95eae1c3 [DAGCombiner] Add a combine to turn a build vector of zero extends of extract vector elts into a vector zero extend and possibly an extract subvector.
llvm-svn: 329509
2018-04-07 19:09:50 +00:00
Tim Northover e25e458d52 Reapply ARM: Do not spill CSR to stack on entry to noreturn functions
Should fix UBSan bot by also checking there's no "uwtable" attribute
before skipping. Otherwise the unwind table will be useless since its
moves expect CSRs to actually be preserved.

A noreturn nounwind function can be expected to never return in any way, and by
never returning it will also never have to restore any callee-saved registers
for its caller. This makes it possible to skip spills of those registers during
function entry, saving some stack space and time in the process. This is rather
useful for embedded targets with limited stack space.

Should fix PR9970.

Patch mostly by myeisha (pmb).

llvm-svn: 329494
2018-04-07 10:57:03 +00:00
Vitaly Buka de5f196530 Revert "ARM: Do not spill CSR to stack on entry to noreturn functions"
Breaks ubsan test TestCases/Misc/missing_return.cpp on ARM

This reverts commit r329287

llvm-svn: 329486
2018-04-07 05:36:44 +00:00
Matt Davis 13b8331054 [StackProtector] Ignore certain intrinsics when calculating sspstrong heuristic.
Summary:
The 'strong' StackProtector heuristic takes into consideration call instructions.
Certain intrinsics, such as lifetime.start, can cause the
StackProtector to protect functions that do not need to be protected.

Specifically, a volatile variable, (not optimized away), but belonging to a stack
allocation will encourage a llvm.lifetime.start to be inserted during
compilation. Because that intrinsic is a 'call' the strong StackProtector
will see that the alloca'd variable is being passed to a call instruction, and
insert a stack protector. In this case the intrinsic isn't really lowered to a
call. This can cause unnecessary stack checking, at the cost of additional
(wasted) CPU cycles.

In the future we should rely on TargetTransformInfo::isLoweredToCall, but as of
now that routine considers all intrinsics as not being lowerable. That needs
to be corrected, and such a change is on my list of things to get moving on.

As a side note, the updated stack-protector-dbginfo.ll test always seems to
pass.  I never see the dbg.declare/dbg.value reaching the
StackProtector::HasAddressTaken, but I don't see any code excluding dbg
intrinsic calls either, so I think it's the safest thing to do.

Reviewers: void, timshen

Reviewed By: timshen

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D45331

llvm-svn: 329450
2018-04-06 20:14:13 +00:00
Mandeep Singh Grang e92f0cfe34 [CodeGen] Change std::sort to llvm::sort in response to r327219
Summary:
r327219 added wrappers to std::sort which randomly shuffle the container before sorting.
This will help in uncovering non-determinism caused due to undefined sorting
order of objects having the same key.

To make use of that infrastructure we need to invoke llvm::sort instead of std::sort.

Note: This patch is one of a series of patches to replace *all* std::sort to llvm::sort.
Refer the comments section in D44363 for a list of all the required patches.

Reviewers: bogner, rnk, MatzeB, RKSimon

Reviewed By: rnk

Subscribers: JDevlieghere, javed.absar, llvm-commits

Differential Revision: https://reviews.llvm.org/D45133

llvm-svn: 329435
2018-04-06 18:08:42 +00:00
Francis Visoiu Mistrih 537d7eee90 [MIR] Add support for MachineFrameInfo::LocalFrameSize
MFI.LocalFrameSize was not serialized.

It is usually set from LocalStackSlotAllocation, so if that pass doesn't
run it is impossible do deduce it from the stack objects. Until now, this
information was lost.

llvm-svn: 329382
2018-04-06 08:56:25 +00:00
Tim Northover b30388bf11 ARM: Do not spill CSR to stack on entry to noreturn functions
A noreturn nounwind function can be expected to never return in any way, and by
never returning it will also never have to restore any callee-saved registers
for its caller. This makes it possible to skip spills of those registers during
function entry, saving some stack space and time in the process. This is rather
useful for embedded targets with limited stack space.

Should fix PR9970.

Patch by myeisha (pmb).

llvm-svn: 329287
2018-04-05 14:26:06 +00:00
Sam Parker 0e7deb8104 [DAGCombine] Revert r329160
Again, broke the big endian stage 2 builders.

llvm-svn: 329283
2018-04-05 13:46:17 +00:00
Puyan Lotfi 8afc99363b [MIR-Canon] Fixing warnings in Non-assert builds.
llvm-svn: 329258
2018-04-05 06:56:44 +00:00
Puyan Lotfi d6f7313c8f [MIR-Canon] Improving performance by switching to named vregs.
No more skipping thounsands of vregs. Much faster running time.

llvm-svn: 329246
2018-04-05 00:27:15 +00:00
Puyan Lotfi 26c504fe1e [MIR-Canon] Adding support for multi-def -> user distance reduction.
llvm-svn: 329243
2018-04-05 00:08:15 +00:00
Jessica Paquette bccd18b816 [MachineOutliner] Add `useMachineOutliner` target hook
The MachineOutliner has a bunch of target hooks that will call llvm_unreachable
if the target doesn't implement them. Therefore, if you enable the outliner on
such a target, it'll just crash. It'd be much better if it'd just *not* run
the outliner at all in this case.

This commit adds a hook to TargetInstrInfo that returns false by default.
Targets that implement the hook make it return true. The outliner checks the
return value of this hook to decide whether or not to continue.

llvm-svn: 329220
2018-04-04 19:13:31 +00:00
Pavel Labath 0cc0306a75 Fix build breakage from r329201
Some compilers do not like having an enum type and a variable with the
same name (AccelTableKind). I rename the variable to TheAccelTableKind.

Suggestions for a better name welcome.

llvm-svn: 329202
2018-04-04 14:54:08 +00:00
Pavel Labath 6088c23431 Re-commit r329179 after fixing build&test issues
- MSVC was not OK with a static_assert referencing a non-static member
  variable, even though it was just in a sizeof(expression). I move the
  assert into the emit function, where it is probably more useful.
- Tests were failing in builds which did not have the X86 target
  configured. Since this functionality is not target-specific, I have
  removed the target specifiers from the .ll files.

llvm-svn: 329201
2018-04-04 14:42:14 +00:00
Nico Weber 55fcd07d25 Revert r329179 (and follow-up unsuccessful fix attempts 329184, 329186); it doesn't build.
llvm-svn: 329190
2018-04-04 13:06:22 +00:00
Nico Weber be6a9b6d7d Attempt to fix bots more after r329179.
llvm-svn: 329186
2018-04-04 12:58:49 +00:00
Nico Weber 7e654e3231 Attempt to fix bots after r329179.
llvm-svn: 329184
2018-04-04 12:54:34 +00:00
Pavel Labath 69baab103a [CodeGen] Generate DWARF v5 Accelerator Tables
Summary:
This patch adds a DwarfAccelTableEmitter class, which generates an
accelerator table, as specified in DWARF v5 standard. At the moment it
only generates a DIE offset column and (if we are indexing more than one
compile unit) a CU column.

Indexing type units is not currently supported, as we don't even have
the ability to generate DWARF v5-compatible compile units.

The implementation is not data-source agnostic like the one generating
apple tables. This was not necessary as we currently only have one user
of this code, and without a second user it was not obvious to me how to
best abstract this. (The difference between these tables and the apple
ones is that they need a lot more metadata about the debug info they are
indexing).

The generation is triggered by the --accel-tables argument, which
supersedes the --dwarf-accel-tables arg -- the latter was a simple
on-off switch, but not we can choose between two kinds of accelerator
tables we can generate.

This is tested by parsing the generated tables with llvm-dwarfdump and
the DWARFVerifier, and I've also checked that GNU readelf is able to
make sense of the tables.

Differential Revision: https://reviews.llvm.org/D43286

llvm-svn: 329179
2018-04-04 12:28:20 +00:00
Sam Parker 7ec722d603 [DAGCombine] Improve ReduceLoadWidth for SRL
Recommitting rL321259. Previosuly this caused an issue with PPCBE but
I didn't receieve a reproducer and didn't have the time to follow up.
If the issue appears again, please provide a reproducer so I can fix
it.

Original commit message:

If the SRL node is only used by an AND, we may be able to set the
ExtVT to the width of the mask, making the AND redundant. To support
this, another check has been added in isLegalNarrowLoad which queries
whether the load is valid.

Differential Revision: https://reviews.llvm.org/D41350

llvm-svn: 329160
2018-04-04 09:26:56 +00:00
Jessica Paquette d506bf8e3d [MachineOutliner][NFC] Make outlined functions have internal linkage
The linkage type on outlined functions was private before. This meant that if
you set a breakpoint in an outlined function, the debugger wouldn't be able to
give a sane name to the outlined function.

This commit changes the linkage type to internal and updates any tests that
relied on the prefixes on the names of outlined functions.
 

llvm-svn: 329116
2018-04-03 21:36:00 +00:00
Jun Bum Lim 7ab1b32b5e [CodeGen]Add NoVRegs property on PostRASink and ShrinkWrap
Summary:
This change declare that PostRAMachineSinking and ShrinkWrap require NoVRegs
property, so now the MachineFunctionPass can enforce this check.
These passes are disabled in NVPTX & WebAssembly.

Reviewers: dschuff, jlebar, tra, jgravelle-google, MatzeB, sebpop, thegameg, mcrosier

Reviewed By: dschuff, thegameg

Subscribers: jholewinski, jfb, sbc100, aheejin, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D45183

llvm-svn: 329095
2018-04-03 18:17:34 +00:00
Puyan Lotfi 764b386e20 Adding optional Name parameter to createVirtualRegister and createGenericVirtualRegister.
llvm-svn: 329076
2018-04-03 15:53:49 +00:00
Rafael Espindola 8c58750cc4 Align stubs for external and common global variables to pointer size.
This patch fixes PR36885: clang++ generates unaligned stub symbol
holding a pointer.

Patch by Rahul Chaudhry!

llvm-svn: 329030
2018-04-02 23:20:30 +00:00
Jonas Devlieghere 9e3e7a99e8 [dsymutil] Upstream emitting of papertrail warnings.
When running dsymutil as part of your build system, it can be desirable
for warnings to be part of the end product, rather than just being
emitted to the output stream. This patch upstreams that functionality.

Differential revision: https://reviews.llvm.org/D44639

llvm-svn: 328965
2018-04-02 10:40:43 +00:00
Sanjay Patel 6124cae8f7 [DAGCombine] (float)((int) f) --> ftrunc (PR36617)
fptosi / fptoui round towards zero, and that's the same behavior as ISD::FTRUNC, 
so replace a pair of casts with the equivalent node. We don't have to account for 
special cases (NaN, INF) because out-of-range casts are undefined.

Differential Revision: https://reviews.llvm.org/D44909

llvm-svn: 328921
2018-03-31 17:55:44 +00:00
Puyan Lotfi 57c4f38c35 [MIR-Canon] Adding support for local idempotent instruction hoisting.
llvm-svn: 328915
2018-03-31 05:48:51 +00:00
Fangrui Song 956ee79795 Fix a bunch of typoes. NFC
llvm-svn: 328907
2018-03-30 22:22:31 +00:00
Puyan Lotfi 399b46c98d [MIR] Adding support for Named Virtual Registers in MIR.
llvm-svn: 328887
2018-03-30 18:15:54 +00:00
Tim Shen 1a8c6776a3 [BlockPlacement] Disable block placement tail duplciation in structured CFG.
Summary:
Tail duplication easily breaks the structure of CFG, e.g. duplicating on
a region entry. If the structure is intended to be preserved, then we
may want to configure tail duplication, or disable it for structured
CFG. From our benchmark results disabling it doesn't cause performance
regression.

Notice that this currently affects AMDGPU backend. In the next patch, I
also plan to turn on requiresStructuredCFG for NVPTX.

All unit tests still pass.

Reviewers: jlebar, arsenm

Subscribers: jholewinski, sanjoy, wdng, tpr, hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D45008

llvm-svn: 328884
2018-03-30 17:51:00 +00:00
Sanjay Patel e09b7dcf3d [SelectionDAG] Removing FABS folding from DAGCombiner
The code has bugs dealing with -0.0.

Since D44550 introduced FABS pattern folding in InstCombine, 
this patch removes the now-redundant code that causes 
https://bugs.llvm.org/show_bug.cgi?id=36600.

Patch by Mikhail Dvoretckii!

Differential Revision: https://reviews.llvm.org/D44683

llvm-svn: 328872
2018-03-30 15:42:52 +00:00
Eli Friedman 208fe67a78 [MachineCopyPropagation] Handle COPY with overlapping source/dest.
MachineCopyPropagation::CopyPropagateBlock has a bunch of special
handling for COPY instructions. This handling assumes that COPY
instructions do not modify the source of the copy; this is wrong if
the COPY destination overlaps the source.

To fix the bug, check explicitly for this situation, and fall back to
the generic instruction handling.

This bug can't happen for most register classes because they don't
have this sort of overlap, but there are a few register classes
where this is possible. The testcase uses the AArch64 QQQQ register
class.

Differential Revision: https://reviews.llvm.org/D44911

llvm-svn: 328851
2018-03-30 00:56:03 +00:00
Rafael Espindola 4b4d85fd4d Style update. NFC.
Rename 3 functions to start with lowercase letters. Don't repeat the
name in the comments.

llvm-svn: 328848
2018-03-29 23:32:54 +00:00